Events in Ukraine have taken another dramatic turn. Russian forces now control Ukraine's Crimean peninsula. The Ukrainian government in Kiev is calling up its military reserves. Secretary of State John Kerry says Russia's military incursion is an incredible act of aggression. Kerry will meet with the new Ukrainian government in Kiev on Tuesday.

So far, the largely pro-Russian Crimea has come under effective Russian control without violence. Officials are warning, though, that the situation could turn bloody with a single mistake in judgment.

NPR's Peter Kenyon is in the Crimean capital, Simferopol. Peter, we're hearing that Ukraine is firing its navy chief after he publicly joined the new Crimean administration. Can you tell us what Crimean Prime Minister Sergei Aksyonov is saying in his audio clip?

SERGEI AKSYONOV: (Foreign language spoken)

PETER KENYON, BYLINE: He's reading out an order that he signed, and it decrees that all Ukrainian naval personnel stationed in Sevastopol in Crimea should stop obeying orders from Kiev, or as Aksyonov puts it, the self-proclaimed officials in the Ukraine. Kiev says Aksyonov himself is self-opponent, of course. Later in this same clip, the naval commander who's standing right next to him, Denis Berezovsky, who was only appointed a day earlier, changes sides and swears loyalty to the supreme commander of the autonomous republic of Crimea. That would be Prime Minister Aksyonov.

We should note that Ukraine still says its fleet of 10 vessels is in the Port of Sevastopol. It hasn't left and remains loyal to Ukraine. So although Aksyonov is declaring the birth of the Crimean navy there, some of that remains to be seen. And we should note that there are other bases surrounded by Russian military men. And those young men are refusing to surrender, hanging onto their weapons, but so far not moving off their bases.

RATH: Wow. Peter, you've been out and about today in Simferopol. What's the mood like there, and what have you seen?

KENYON: Well, we specifically went looking for these buildings being guarded. And there are armed guards in front of most key government and military buildings, sometimes Russian forces. Sometimes they're regular units of local pro-Russian Crimeans, much more lightly armed. Residents, however, are continuing with daily life for the most part, although the streets seem a bit quieter we're told. And some people have left.

We spoke today with a group of older Crimeans born here when it was part of the Soviet Union. They were quite thrilled at the prospect of being part of Russia again. Others, however, insist that they really don't need to be part of Russia. They'd just like more independence from Kiev than they have now.

RATH: Well, it sounds like Crimea is effectively under Russian control, but what about Eastern Ukraine, which also has a strong pro-Russian population?

KENYON: Well, this is what a lot of people are talking about: much speculation. Crimea, of course, has the special historical ties to Russia in the former Soviet Union, but much of Eastern Ukraine shares the same pro-Russian slant or leaning. One scenario people are discussing is whether Crimea becomes a kind of model for Eastern Ukraine. And we see pushes for more autonomy in other cities like Kharkiv and Donetsk and elsewhere.

And this would be a huge headache for Kiev and the Ukrainian government because much of the important industrial activity takes place there. So this is probably one scenario Europe in particular is fearing greatly.

RATH: And in Kiev, the government is mobilizing its forces and calling up reserves, but do people there really expect a military showdown over Crimea?

KENYON: Well, most people don't expect it. They think it's laughable, a clear mismatch in military capability in favor of the Russians. On the other hand, you can't control patriotic passions. It wouldn't take much to change this from a bloodless incursion to something very bloody indeed. And that's why we're seeing all the calls for de-escalation. And that raises the question, well, what will Russian leader Vladimir Putin want in order to pull things back?